Roof Truss Minimum Pitch

This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement.

Roof truss minimum pitch.

Calculate the height of a common truss using the building width and the slope of the roof. Wilson roof truss ltd. For example if you use a heavy load of asphalt shingles a minimum pitch of 2 12 is needed for proper drainage. I e 4 inches of rise per 12 inches one foot of run.

Note that roof pitch is sometimes used in parallel with roof slope. However roof pitch is technically measured and defined differently and will not be discussed here. The picture below shows the pitch of a 7 12 roof slope meaning that for 12 of horizontal measurement roof run the vertical measurement roof rise is 7. Depending on your roof slope add 4 to 5 inches for heel height.

To get the minimum pitch for a metal roof the vertical rise per foot is divided by the horizontal slope. The best outcome of the pitch depends on the covering of the roof. Rafter length from rise. Most metal roofs will have minimum pitches of three in twelve but this might sometimes go down depending on whether there are special installation procedures issued by the manufacturer regarding that particular roofing material.